I have the standard Sat Nav unit in my '06 plate Focus, and would like to know if there is any way of playing music via Bluetooth from my phone?
I have an AUX cable but it looks untidy and I can't close the glovebox whilst in use, having to keep plugging it in and not being able to reach the phone whilst driving is also a little annoying.

There is quite a lot of dongles like this, I got this one after doing some research online. For comfortable use you would have to fit new AUX port in centre console area or use 3.5mm jack extension cable, hide it under dash and put it's end where you can reach.

Funnily enough, I did read your post before writing mine to see if there was a wireless option.

I did come across ones like these, but the jack would mean I couldn't close the glovebox, and I'm not sure whether it would be compatible with the sat nav unit?

My original plan was to purchase an aux cable with one right angle end as shown here (so it can be plugged in and the glove box closed, feeding the wire through a drilled hole), then as you mentioned, run it behind the dash and have it either coming out underneath the demist swiches, or coming out of the armrest.

Just bypass the existing aux connector and plug this into the back of the radio socket where the original one goes.
Run the wire down to the underside of the demister switches and out near the 12v socket.
I use the same thing for plugging into my iPod connector/controller and it works a charm.
Far easier than reaching into the glovebox every time you want to get to the phone.

I did come across ones like these, but the jack would mean I couldn't close the glovebox, and I'm not sure whether it would be compatible with the sat nav unit?

This kind of adapters / dongles are universal and all they require is AUX port. I prefer to buy good quality things as long as it is possible and this is why I decided to buy HTC instead of cheaper one. Reviews confirmed also very good sound quality.

Regarding the cable - you can choose either your option (but I do not think angled jack is required to close glove box, standard jack did not cause me any trouble) or the one advised by Stoney. In case u want to use it with BT dongle you could get something like this